BUG#25712 - insert delayed and check table run together report
crashed tables
Let MY_THREADSAFE have distinct value. Some functions call my_seek
passing MyFlags argument directly to it. This may cause unnecessary
locks, which may finally lead to a dead-lock (specifically see my_lock).
tables
In case system doesn't have native pread/pwrite calls (e.g. Windows)
and there is CHECK TABLE runs concurrently with another statement that
reads from a table, the table may be reported as crashed.
This is fixed by locking file descriptor when my_seek is executed on
MyISAM index file and emulated pread/pwrite may be executed concurrently.
Affects MyISAM tables on platforms that do not have native
pread/pwrite calls (e.g. Windows).
No deterministic test case for this bug.
for a query over an empty table right after its creation.
The crash is the result of an attempt made by JOIN::optimize to evaluate
the WHERE condition when no records have been actually read.
The added test case can reproduce the crash only with InnoDB tables and
only with 5.0.x.
statement from a UNION query with ORDER BY an expression containing
RAND().
The crash happened because the global order by list in the union query
was not re-initialized for execution.
(Local order by lists were re-initialized though).
- Queries in the query cache are identified by the individual
characters in the query statement, the current database and
the current environment expressed as a set of system variable
flags.
- Since the set of environment flags didn't properly describe the
current environment unexpected results were returned from the
query cache.
- Query cache is now cleared when the variable ft_boolean_syntax is
updated.
- An identification flag for the variable default_week_format is
added to the query cache record.
Thanks to Martin Friebe who has supplied significant parts of this patch.
When checking for applicability of join cache
we must disable its usage only if there is no
temp table in use.
When a temp table is used we can use join
cache (and it will not make the result-set
unordered) to fill the temp table. The filesort()
operation is then applied to the data in the temp
table and hence is not affected by join cache
usage.
Fixed by narrowing the condition for disabling
join cache to exclude the case where temp table
is used.
The generic string to int conversion was used by the Item_func_signed and
the Item_func_unsigned classes to convert DATE/DATETIME values to the
SIGNED/UNSIGNED type. But this conversion produces wrong results for such
values.
Now if the item which result has to be converted can return its result as
longlong then the item->val_int() method is used to allow the item to carry
out the conversion itself and return the correct result.
This condition is checked in the Item_func_signed::val_int() and the
Item_func_unsigned::val_int() functions.
some rollup rows (rows with NULLs for grouping attributes) if GROUP BY
list contained constant expressions.
This happened because the results of constant expressions were not put
in the temporary table used for duplicate elimination. In fact a constant
item from the GROUP BY list of a ROLLUP query can be replaced for an
Item_null_result object when a rollup row is produced .
Now the JOIN::rollup_init function wraps any constant item referenced in
the GROYP BY list of a ROLLUP query into an Item_func object of a special
class that is never detected as constant item. This ensures creation of
fields for such constant items in temporary tables and guarantees right
results when the result of the rollup operation first has to be written
into a temporary table, e.g. in the cases when duplicate elimination is
required.
INSERT...ON DUPLICATE KEY UPDATE may cause error 1032:
"Can't find record in ..." if we are inserting into
InnoDB table unique index of partial key with
underlying UTF-8 string field.
This error occurs because INSERT...ON DUPLICATE uses a wrong
procedure to copy string fields of multi-byte character sets
for index search.
This bug occurs when error message length exceeds allowed limit: my_error()
function outputs "%s" sequences instead of long string arguments.
Formats like %-.64s are very common in errmsg.txt files, however my_error()
function simply ignores precision of those formats.
